I'm new to Mathematica and have a question regarding matrices. I was
sure that this problem must have been answered in the past, but could
not find a solution.
I want to replace some elements in a matrix (based on value) with
elements from another matrix at the same position. Eg:
a = {{0, 1}, {1, 2}};
b = {{1, 3}, {2, 5}};
I want to replace the elements in "a" which are equal to 1 (say) with
the same position elements in b to give:
c = {{0, 3}, {2, 2}};
How can I do this? I started with using Position and ReplacePart but
could not figure out how to get it to work in this case (other cases
are documented, such as replacing with a single value).
Any help appreciated. Thanks.